MILWAUKEE, May 19 (Reuters) - Seven people were injured on Monday in an explosion at a foundry in Wisconsin, rescue personnel and local media said.

The incident at Johnson Brass and Machine Foundry in Saukville happened at about 4 p.m. local time, a dispatcher with the Ozaukee County Sheriff's Department said.

The dispatcher said seven people were injured, but did not know the extent of the injuries or the cause of the explosion. Several area fire departments responded, the dispatcher said.

Molten metal spilled on employees at the foundry, which is located 25 miles (40 km) north of Milwaukee, a plant supervisor told WISN television, an ABC affiliate in Milwaukee. (Editing by David Bailey, Ken Wills and Eric Walsh)